In conventional mobile communication systems, broadcast communication has been known in which, as shown in FIG. 1, one or more base stations BS simultaneously transmit the same information to an unspecified large number of mobile stations UE (User Equipments) in a given cell or cells (e.g., see non-patent literature 1).
Also, in the conventional mobile communication systems, multicast communication has been known in which, as shown in FIG. 2, the same information is transmitted to a plurality of mobile stations UE belonging to a particular group (e.g., see non-patent literature 2).
Mobile stations UE used in the conventional mobile communication systems have two types of mode, “Idle mode” and “Connected mode”, as shown in FIG. 3.
The “Idle mode” is a mode in which an RRC (Radio Resource Control) connection is not established between the mobile station UE and a radio network controller RNC, that is, a mode in which a radio network controller RNC does not need to keep track of location information on the mobile station UE. On the other hand, the “Connected mode” is a mode in which an RRC connection is established between the mobile station UE and a radio network controller RNC. Establishment and release of an RRC connection change the mode of the mobile station UE as shown in FIG. 3.
An RRC connection is established between a mobile station UE and a radio network controller RNC, by a UE originated call from the mobile station UE or a reception of paging by the mobile station UE in the “Idle mode”.
With reference to FIG. 4, the way in which an RRC connection is established when a mobile station UE in the “Idle mode” receives paging will be described.
As shown in FIG. 4, a switched network CN (Core Network) transmits, to a radio network controller RNC, a paging signal for a call in to the mobile station UE; and the radio network controller RNC transmits the paging signal to the mobile station UE. When the mobile station UE determines that the received paging signal is a signal to itself, it performs an RRC connection establishment procedure with the radio network controller RNC and makes the transition to the “Connected mode”.
<Non-Patent Literature 1>
3rd Generation Partnership Project Technical Specification Group Terminals, 23.041 Technical realization of Cell Broadcast Service (CBS), October, 2000
<Non-Patent Literature 2>
3rd Generation Partnership Project Technical Specification Group Radio Access Network, 25.324 Broadcast/Multicast Control BMC, December, 2000
However, in the broadcast communication or the multicast communication in the conventional mobile communication systems, there is the problem that since a mobile station UE in the “Idle model” cannot establish a dedicated channel (such as a DCCH (Dedicated Common Control Channel) or DTCH (Dedicated Transport Channel)), a radio network controller RNC does not have any means of determining to which broadcast communication or multicast communication control information transmitted from the mobile stations UE through a common channel relates.
The present invention has been made in view of the above problem, and has an object of providing a mobile station which enables transmission of control information on broadcast communication or multicast communication to a radio network controller without establishing a dedicated channel in broadcast communication or multicast communication.